The compound Na2ZnV2O7 with an åkermanite-type structure has been synthesized. It has a tetragonal unit cell, a=8.2711(4), c=5.1132(2) Å, and crystallizes with P-421m symmetry, Z=2. Its crystal structure has been refined from a combination of X-ray and neutron powder diffraction data. The structure contains layers of corner-sharing VO4 and ZnO4 tetrahedra, the former in pairs forming pyrovanadate V2O7 units. The sodium atoms are positioned between the layers, with a distorted antiprismatic coordination of oxygen atoms.

The X-ray Rietveld refinement technique was used to determine the structure and prepare X-ray powder reference patterns for the phases R2Cu9Ti12O36 (R=Nd, Sm, Eu, Gd, Dy, Ho, Y, Er, Tm, Yb, and Lu). R2Cu9Ti12O36 belongs to the perovskite-related [AC3](B4)O12 family of structures, which are cubic with space group Im3. The lattice parameters of the R2Cu9Ti12O36 series range from a=7.377 57(2) Å, V=401.550(3) Å3 for R=Lu to a=7.399 87(3) Å, and V=405.202(4) Å3 for R=Nd. The trend of these lattice parameters parallels the “lanthanide contraction.” In the structure, R occupies the larger icosahedral A site of the ideal ABO3 perovskite structure, while Ti occupies the distorted octahedral B site. The Jahn-Teller cation Cu occupies the C site. The twelve oxygens surrounding Cu are arranged as three mutually perpendicular rectangles of different size. The smallest and largest rectangles are nearly squares. One-third of the R site is vacant, and the chemical formula can be written as [R2∕3X1∕3Cu3](Ti4)O12, where X=vacancy. The X-ray powder patterns of R2Cu2Ti12O36 have been submitted to ICDD for inclusion in the Powder Diffraction File (PDF).

The Nowotny chimney–ladder compound VGe1.82 was redetermined from powder diffraction data and modelled with the incommensurately modulated composite approach. The dimensions of the tetragonal unit subcells are a=5.9015(3) Å, cGe=2.6916(2)Å, and cV=4.9080(2)Å and the one-dimensional modulation vectors are qGe=0.45159(1)[001]* and qV=0.17656(1)[001]*. Comparison is made with a previous reported commensurate approximation of the structure with a 31-fold cGe axis.

Potassium tetraperoxomolybdate (VI) K2[Mo(O2)4] was prepared, and its X-ray powder diffraction pattern was recorded at low temperature (258 K). The unit cell parameters were refined to a=10.7891(2) Å, α=64.925(3)°, space group R−3c (167), Z=6. The compound is isostructural with potassium tetraperoxotungstate (VI) K2[W(O2)4] (Stomberg, 1988). The sample of K2[Mo(O2)4] was characterized by analytical investigations, and the results of crystal structure refinement by Rietveld method are presented; final RP and RWP are 9.79% and 12.37%, respectively.

The low-cristobalite-type modification of Al0.5Ga0.5PO4 is prepared by annealing the amorphous precipitate of stoichiometric phosphate at 1300 °C. The phase purity of the sample is ascertained by powder X-ray diffraction. The crystal structure is refined by Rietveld refinements of the neutron and X-ray diffraction data of the polycrystalline powder. This compound crystallizes in an orthorhombic lattice with unit cell parameters, a=7.0295(8), b=7.0132(8), and c=6.9187(4) Å, V=341.08(6) Å3, Z=4 (Space group C 2221, No. 20). The crystal structure analysis reveals the random distribution of the Al3+ and Ga3+ having tetrahedral coordination with typical M–O (M=Al3+:Ga3+) bond lengths as 1.74 Å. Similarly, the P5+ have tetrahedral coordination with typical P–O bond lengths 1.52–1.54 Å. The Mo4 and PO4 tetraheda are linked by common corners forming a three-dimensional framework lattice. The details of the crystal structure are presented in this paper.

The title compound, ∣Na6Li1.6K0.4Cl2∣[Al6Si6O24]‐SOD, is similar to sodalite proper, but the introduction of Li and K into the structure creates a reduction in unit-cell volume and additional collapse of the framework tetrahedra. Refinement of an X-ray powder diffraction pattern of a multiphase material yielded for sodalite a lattice parameter of 0.88427 (2) nm, an Al–O–Si bond angle of 137.9(3°), and Al–O and Si–O bond lengths of 0.1730(5) nm and 0.1620(5) nm, respectively. The angle of the unique Al–O–Si bond corresponds well with the 138° obtained by 29Si solid-state magic-angle-spinning nuclear magnetic resonance spectroscopy. This characterization is important since the compound constitutes an essential part of a radioactive waste form intended for a high-level waste repository.

A new compound Th0.9Ce0.1SiO4, iso-typic to zircon, was prepared by heating predried ThO2, CeO2, and SiO2 (in the mole ratio 0.9:0.10:1.0) by a two-step heating protocol. The polycrystalline sample obtained was characterized by Rietveld refinement of the observed neutron diffraction data with the starting model of tetragonal ThSiO4. It has a body centered tetragonal structure with space group I41∕amd and four formula units per unit cell. The unit-cell parameters are a=7.1238(4) Å and c=6.3186(95) Å. The RP, Rwp, and Re factors are 7.77%, 10.9%, and 4.85%, respectively. The incorporation of about 10 mol % cerium was used to stabilize the tetragonal modification of ThSiO4.

Materials in the Ti–Al–C ternary system commonly contain three coexisting phases, Ti3AlC2, Ti2AlC, and TiC. Quantitative phase analysis in this ternary system was investigated using X-ray diffraction. First, nonoverlap diffraction peaks were selected: the (002) peak at 2θ=9.5° for Ti3AlC2 (I∕I0=26.5), the (002) peak at 2θ=13.0° for Ti2AlC (I∕I0=39), and the (111) peak at 2θ=35.9° for TiC (I∕I0=78), respectively. Then, based on the mixing-sample method without internal standards, a set of equations was derived for determining the amounts of Ti3AlC2, Ti2AlC, and TiC in a sample using the intensities of the selected diffraction peaks. Finally, the applicability and error sources for this method were investigated. The method is simple and straightforward, and is applicable to the entire Ti–Al–C ternary system, since the derivation of this equation group is self-checking.

Laboratory powder X-ray microdiffraction with a focusing monocapillary and linear multichannel detector was applied to phase identification in fragments of painting layers of art works, canvas and wall paintings, and polychromes on wood. This method is useful in materials research of painting layers with complex stratigraphy, and it is indispensable in distinguishing inorganic pigments of different natural provenance and revealing degradation products. The advantage of X-ray microdiffraction is its nondestructive nature and no need of sample pretreatment. Samples after microdiffraction can hence be used for other analyses or archived. Another advantage is the possibility to work with samples smaller than 1 mm, which is particularly important in the analysis of artworks where the sample amount or size is a serious limit of using the laboratory techniques of materials research. The X-ray equipment used is more economical and more easily accessible than other microdiffraction techniques and is, hence, suitable for routine analytical work.

This study attempted to quantify the interstratificational broadening of the randomly interstratified illite/smectite (random I∕S) basal reflection and to evaluate the percentage of the interstratified illite layers (%I) from the result. The interstratificational broadening was quantified using the distributional discrepancy (D) defined as D=[∑t∣ft(obs)−ft(ref)∣]∕2, where ft(obs) is the frequency of a crystallite containing thickness, t (the number of layers), measured from a basal reflection broadened by interstratifications, and ft(ref) is the frequency for a basal reflection with no interstratificational broadening. The basal reflections at 5.2° 2θ under glycolation and 8.84° 2θ under thermal dehydration provided the ft(obs) and ft(ref) of random I∕S. The linear relation, D=2.17%I+2.49(0⩽%I⩽30), was obtained from simulations for SWy-2 (Wyoming, USA).

A direct method for determining powder diffraction data from a range of depths is described, where the linear absorption coefficient may vary with depth. A series of traditional data collections with varying angles of incidence are required, and the X-ray diffraction data arising from specific depths will be calculated by the transformation of these measured, angle-dependent spectra. These may then be analysed using any conventional method in order to gain information about characteristics of the sample in question at specific depths. Regularisation techniques have been used to solve the governing Fredholm integral equation to determine the depth-dependent diffractograms. The method has been validated by the use of simulated data having known model profiles, and has also been applied to experimental data from polycrystalline thin film samples.

The room temperature powder pattern of abacavir hemisulfate (anti-HIV reverse transcriptase compound) was indexed using 2θ values obtained from a powder pattern spiked with an internal standard. The resulting unit cell values for the monoclinic I2 cell [nonstandard setting of C2 (No. 5)] are a=13.278(1) Å, b=8.437(1) Å, c=14.259(2) Å, β=93.87(1)°. There are two formula units [(C14H16N6O)2.H2SO4] per unit cell and Dx=1.390 g∕cm3.

Four heterometallic carbonyl complexes: (1) Cp(CO)2MnPt(μ-C=CHPh)dppm) (2) [Cp(CO)2MnCu(μ-C=CHPh)(μ-Cl)]2, (3) CpMnFe2(μ3-C=CHPh)(CO)8, and (4) η4-[Cp(CO)2MnC(CO)CHPh]Fe(CO)3 have been studied by X-ray powder diffraction and their unit cell parameters are reported. Orthorhombic cell parameters for complex (1) are a=18.5719(14) Å, b=18.6092(14) Å, c=23.8117(18) Å, Z=8, space group Pbca. Monoclinic cell parameters found for complex (2) are a=11.5816(5) Å, b=7.9784(5) Å, c=16.7819(7) Å, β=105.460(2)°, Z=2, space group P21∕n. Orthorhombic cell parameters for complex (3) are a=13.5260(9) Å, b=15.1487(10) Å, c=10.3330(6) Å, Z=4, space group Pna21. Monoclinic cell parameters for complex (4) are a=10.3545(45) Å, b=8.0002(43) Å, c=21.8355(95) Å, β=102.89(2), Z=4, space group P21∕c. Parameters found for complexes (1–4) are in good agreement with those obtained from single crystal X-ray diffractometry.

A series of mixed fluoride compositions with PbF2 and ScF3 were prepared by heating the intimate mixtures of component fluorides at 600 °C for 10 h followed by slowly cooling to room temperature. The products obtained were analyzed by powder XRD to reveal the phases present in them and hence the low-temperature phase equilibria in the PbF2-ScF3 system. The phase equilibria show the fluorite-type solid solution up to the composition of about 15 mol% of ScF3 in the PbF2 lattice. The unit cell volume decreases with increasing ScF3 contents in the fluorite-type solid solutions. Beyond the solubility limit, the biphasic mixture of the cubic fluorite-type solid solution and leftover ScF3 is found to exist.

Drilling a hole in the blade of a vibrating spatula makes a simple tool for both handling and filling capillary tubes. It is especially useful for filling capillaries with air-sensitive samples in a glove box.